Light control device and light control method

Abstract

To provide a dimming device that individually changes a dimming rate of each of a plurality of dimmer members.SOLUTION: A dimming device 1 for individually changing a dimming rate of each of a plurality of dimmer members 2 includes: a DC / AC inverter 10 capable of converting a DC voltage comprising a first voltage value into an AC voltage having a predetermined first cycle; and a control part 20 for controlling the DC / AC inverter 10 so that the AC voltage cycle includes an output voltage having a second cycle shorter than the first cycle, based on a PWM control signal of an on-duty ratio corresponding to a desired dimming rate at each of the plurality of dimmer members 2.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a light control device that individually changes the dimming rate of each of a plurality of light control members, and to such a light control method. [Background technology]

[0002] Conventionally, techniques have been used to change the transmittance of light at the portion where the light is incident. For example, one such technique is described in Patent Document 1, the source of which is shown below.

[0003] Patent Document 1 discloses an illuminance control system for a mobile body that is provided in a mobile body with a light-adjusting component disposed at a location where external light is incident. This illuminance control system for a mobile body includes an internal illuminance measurement unit that measures the illuminance inside the mobile body, an external illuminance measurement unit that measures the illuminance outside the mobile body, and a drive control unit that changes the transmittance of the light-adjusting component. The drive control unit changes the transmittance of the light-adjusting component based on a comparison result between the internal illuminance of the mobile body measured by the internal illuminance measurement unit, which is set based on the internal illuminance of the mobile body measured by the internal illuminance measurement unit and the external illuminance of the mobile body measured by the external illuminance measurement unit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-122675 Summary of the Invention [Problem to be solved by the invention]

[0005] When a light control component is provided on a moving body, a light control component may be provided for each of the divided sections. In this case, it is desirable to individually control each of the multiple light control components to change the transmittance (light control ratio). However, the technology described in Patent Document 1 does not disclose a specific configuration or method for individually controlling each of the multiple light control components.

[0006] Therefore, there is a need for a technology that can individually change the dimming rate of each of a plurality of dimming components. [Means for solving the problem]

[0007] A characteristic configuration of the dimming device according to the present invention is that the dimming device is configured to individually change the dimming rate of each of a plurality of dimming components, and includes a DC / AC inverter capable of converting a DC voltage into an AC voltage having a predetermined first period, and a control unit that controls the DC / AC inverter based on a PWM control signal having an on-duty ratio corresponding to the desired dimming rate of each of the plurality of dimming components, so that an output voltage having a second period shorter than the first period is included within the period of the AC voltage.

[0008] With this characteristic configuration, when an AC voltage is output from a single DC / AC inverter in the first cycle, the output can include a voltage corresponding to the dimming ratio of each of the multiple dimming components. Therefore, with this configuration, it is possible to individually change the dimming ratio of each of the multiple dimming components.

[0009] Furthermore, the DC / AC inverter preferably has two arms, each having a first switching element and a second switching element connected in series, arranged between a first power supply line and a second power supply line, and a filter arranged across a first node, at which the first switching element and the second switching element in one of the two arms are connected, and a second node, at which the first switching element and the second switching element in the other of the two arms are connected, and the filter smoothes the output from the two arms to a voltage corresponding to the dimming rate of each of the plurality of dimming members.

[0010] With this configuration, the output voltage of the second cycle included in the AC voltage of the DC / AC inverter can be varied for each period according to the second cycle, thereby making it possible to apply a voltage changed according to a desired dimming rate to each of the multiple dimming components.

[0011] Preferably, the light-adjusting device further includes a cutoff unit having a first cutoff unit provided at a first terminal of each of the plurality of dimming elements and capable of cutting off an electrical connection between the first terminal and the first node, and a second cutoff unit provided at a second terminal of each of the plurality of dimming elements and capable of cutting off an electrical connection between the second terminal and the second node, and the control unit outputs the PWM control signal at the second period and changes the cutoff state of the cutoff unit based on the second period.

[0012] With this configuration, it is possible to apply the voltage output from the DC / AC inverter to the light control member at a predetermined timing synchronized with the second period of the PWM control signal.

[0013] Preferably, the control unit closes the cutoff unit so as to apply only a voltage corresponding to the dimming rate to each of the plurality of dimming members.

[0014] With this configuration, only the voltage corresponding to the dimming rate is applied to each of the multiple dimming components, and it is possible to prevent the voltage corresponding to the dimming rate from being applied to other dimming components of the multiple dimming components, thereby making it possible to maintain a constant dimming rate for each of the multiple dimming components.

[0015] It is also preferable to further include a capacitor connected in parallel to each of the plurality of light adjusting members.

[0016] This configuration makes it possible to suppress a voltage drop due to self-discharge of the dimming component. Therefore, when a voltage corresponding to the dimming rate is applied to another dimming component of the multiple dimming components, the voltage previously applied can be maintained, making it possible to suppress changes in the dimming rate of the dimming component.

[0017] Furthermore, a characteristic configuration of the dimming method according to the present invention is a dimming method in which a computer individually changes the dimming rate of each of a plurality of dimming components, and the dimming method comprises: a setting step of setting an on-duty ratio according to a desired dimming rate of each of the plurality of dimming components; and a control step of controlling a DC / AC inverter capable of converting a DC voltage into an AC voltage having a predetermined first period, based on a PWM control signal of the on-duty ratio, so that an output voltage having a second period shorter than the first period is included in the period of the AC voltage.

[0018] Such a light control method is substantially the same as the light control device described above, and can achieve the same effects as the light control device. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a diagram showing a vehicle equipped with a light control member. [Figure 2] FIG. 2 is a diagram illustrating a circuit configuration of a light control device. [Figure 3] 4A and 4B are diagrams illustrating waveforms of various parts of the light control device. [Figure 4] FIG. 10 is a diagram illustrating the effect of a capacitor. DETAILED DESCRIPTION OF THE INVENTION

[0020] A light control device according to the present invention is configured to be able to individually change the dimming rate of each of a plurality of light control members. A light control device 1 of this embodiment will be described below. FIG. 1 shows a vehicle 3 equipped with a light control member 2 whose dimming rate can be changed by the light control device 1. In this embodiment, two light control members 2 are provided in a sunroof provided on the roof 3A of the vehicle 3, and the light control rate of each light control member 2 can be individually changed to adjust the amount of light irradiated into the vehicle interior. In the following, when distinguishing between the two light control members 2, one will be described as light control member 2A and the other as light control member 2B.

[0021] Fig. 2 is a block diagram that schematically illustrates the configuration of the dimming device 1. As illustrated in Fig. 2, the dimming device 1 of this embodiment includes a DC / AC inverter 10, a second control unit 20, a filter 30, a cutoff unit 40, and a capacitor 50. Each functional unit is constructed using hardware or software, or both, with a CPU as its core component, in order to individually change the dimming rate of each of the multiple dimming components 2. Fig. 2 also illustrates a DC / DC converter 60, a first control unit 70, a power supply unit 80, a signal isolation unit 90, and a vehicle body control device 100.

[0022] The DC / DC converter 60 converts the output voltage of battery B into a predetermined DC voltage and outputs it. Battery B is a battery mounted on the vehicle 3. Therefore, the output voltage of battery B corresponds to the DC voltage output from battery B. Here, the DC voltage output from the DC / DC converter 60 corresponds to the input voltage to the DC / AC inverter 10. Therefore, the DC voltage output from the DC / DC converter 60 corresponds to the DC voltage of the voltage value to be input to the DC / AC inverter 10. Changing the dimming rate of the dimming member 2 performed by the dimming device 1 requires an AC voltage with a large voltage amplitude (for example, 100 V or more). For this reason, it is preferable to use an isolated DC / DC converter in which the primary side and secondary side are insulated as the DC / DC converter 60.

[0023] It should be noted that a step-up DC / DC converter is used as the DC / DC converter 60 if the voltage value of the DC voltage to be input to the DC / AC inverter 10 is higher than the voltage value of the voltage output from battery B, and a step-down DC / DC converter is used if the voltage value of the DC voltage to be input to the DC / AC inverter 10 is lower than the voltage value of the voltage output from battery B. Also, if the voltage value of the voltage output from battery B and the voltage value of the DC voltage to be input to the DC / AC inverter 10 are approximately the same, a step-up / step-down DC / DC converter may be used, or a DC / DC converter may not be used.

[0024] The first control unit 70 is driven by a DC voltage from the battery B and controls the DC / DC converter 60. The first control unit 70, for example, performs PWM control on a switching element included in the DC / DC converter 60 to control the output voltage of the DC / DC converter 60 to a desired voltage value. Therefore, the first control unit 70 may monitor the output voltage of the DC / DC converter 60 and control the output voltage to a desired voltage value by feedback control. Here, in this example, the vehicle body control device 100 receives an operation instruction from the user of the vehicle 3 and instructs the first control unit 70 on the input voltage amplitude to the light control member 2 as an amplitude command. The first control unit 70 transmits the amplitude command from the vehicle body control device 100 to a signal insulating unit 90, which will be described later.

[0025] The signal isolating unit 90 insulates the control signal for controlling the second control unit 20 based on the amplitude command from the vehicle body control device 100 transmitted from the first control unit 70 and transmits the isolated control signal to the second control unit 20. Such a signal isolating unit 90 can be configured using, for example, a photocoupler.

[0026] The power supply unit 80 converts the output voltage of the DC / DC converter 60 into a voltage with a value suitable for driving the second control unit 20. The output voltage of the DC / DC converter 60 is, for example, a DC voltage of 100 V or more. On the other hand, the second control unit 20 corresponds to a controller for driving the DC / AC inverter 10 and drives it with a DC voltage of, for example, about 3.3 V or 5 V. Therefore, the power supply unit 80 steps down the output voltage of the DC / DC converter 60 (for example, 100 V or more) to a voltage with a value suitable for driving the second control unit 20 (3.3 V or 5 V). Such a power supply unit 80 can be configured using a shunt regulator or a switching regulator. Alternatively, when the DC / DC converter 60 is configured using a transformer, an auxiliary winding may be provided separately in the transformer to output a voltage with a value suitable for driving the second control unit 20 that is smaller than the first voltage value corresponding to the output voltage of the DC / DC converter 60.

[0027] The DC / AC inverter 10 is configured to be able to convert a DC voltage having a first voltage value into an AC voltage having a predetermined first period T1 (see FIG. 3 ). In this embodiment, the DC voltage having the first voltage value is the output voltage of the DC / DC converter 60. The predetermined first period T1 corresponds to the period of the AC voltage applied to each of the multiple light-adjusting members 2 in order to change the dimming rate of the light-adjusting members 2, which will be described later. The frequency of the AC voltage according to this first period T1, i.e., the frequency of the AC voltage output by the DC / AC inverter 10, is not particularly limited, but can be, for example, several tens of Hz.

[0028] The DC / AC inverter 10 can be configured to have two arms A, each of which is provided between a first power supply line L1 and a second power supply line L2 and has a first switching element QH and a second switching element QL connected in series. The first power supply line L1 is a power supply line connected to the positive terminal of the two output terminals of the DC / DC converter 60, and the second power supply line L2 is a power supply line connected to the negative terminal of the two output terminals of the DC / DC converter 60. The DC / AC inverter 10 has two arms A between the first power supply line L1 and the second power supply line L2. Hereinafter, when it is necessary to distinguish between the two arms A, one arm A will be referred to as arm A1 and the other arm A will be referred to as arm A2. In this embodiment, when distinguishing between the first switching element QH and the second switching element QL constituting each arm section A, the first switching element QH of the arm section A1 is referred to as the first switching element Q1, and the second switching element QL of the arm section A1 is referred to as the second switching element Q2. Furthermore, the first switching element QH of the arm section A2 is referred to as the first switching element Q3, and the second switching element QL of the arm section A2 is referred to as the second switching element Q4. In this embodiment, both the first switching element QH and the second switching element QL are N-type MOS-FETs. The drain terminal of the first switching element QH is connected to the first power supply line L1, and the source terminal of the first switching element QH is connected to the drain terminal of the second switching element QL. The source terminal of the second switching element QL is connected to the second power supply line L2. A diode DH is parasitically provided between the source and drain terminals of the first switching element QH, with its anode connected to the source terminal and its cathode connected to the drain terminal. Also, a diode DL is parasitically provided between the source and drain terminals of the second switching element QL, with its anode connected to the source terminal and its cathode connected to the drain terminal.2, the diode DH provided between the source terminal and drain terminal of the first switching element Q1 is shown as diode D1, and the diode DL provided between the source terminal and drain terminal of the second switching element Q2 is shown as diode D2. The diode DH provided between the source terminal and drain terminal of the first switching element Q3 is shown as diode D3, and the diode DL provided between the source terminal and drain terminal of the second switching element Q2 is shown as diode D4. The gate terminals of the first switching element QH and the second switching element QL are connected to a second control unit 20, which will be described later. The DC / AC inverter 10 configured in this manner outputs, as an AC voltage, a rectangular wave with a frequency of several tens of hertz and with the output voltage of the DC / DC converter 60 as both its positive and negative amplitudes.

[0029] The second control unit (corresponding to the "control unit") 20 controls the DC / AC inverter 10 based on a PWM control signal with an on-duty ratio corresponding to a desired dimming rate for each of the plurality of dimming components 2 so that an output voltage having a second period T2 (see FIG. 3 ) shorter than the first period T1 is included within the period of the AC voltage (in this example, every half period of the AC voltage). In this embodiment, each of the plurality of dimming components 2 is a dimming component 2A and a dimming component 2B. Here, the dimming rate of the dimming component 2 is configured to be changeable according to the amplitude value of the AC voltage applied between a pair of terminals of the dimming component 2. In this example, the period of the AC voltage is the period of an AC voltage with a frequency of several tens of Hz, and corresponds to the first period T1. The second period T2 corresponds to a control period of the DC / AC inverter 10 by the second control unit 20, and corresponds to a period corresponding to a frequency of, for example, several tens of kHz to several hundreds of kHz. Therefore, the second control unit 20 controls the DC / AC inverter 10 based on a PWM control signal having an on-duty ratio corresponding to the desired dimming rate of each of the dimming members 2A and 2B so that an output voltage having a second period T2, which is a period corresponding to a frequency of, for example, several tens of kHz to several hundreds of kHz, is included every half period of the AC voltage (half period of the first period T1).

[0030] In this example, the second control unit 20 drives the first switching element Q1 and the second switching element Q4 in the second cycle T2 by a PWM control signal having an ON DUTY ratio set according to the dimming rate of the dimming member 2A over the first 1 / 4 period of the first cycle T1 (for example, the period from time t1 to time t2 when the period from time t1 to time t5 in FIG. 3 is defined as the first cycle T1), and drives the first switching element Q1 and the second switching element Q4 in the second cycle T2 by a PWM control signal having an ON DUTY ratio set according to the dimming rate of the dimming member 2B over the next 1 / 4 period of the first cycle T1 (for example, the period from time t2 to time t3 when the period from time t1 to time t5 in FIG. 3 is defined as the first cycle T1). Subsequently, the second control unit 20 drives the first switching element Q3 and the second switching element Q2 with a PWM control signal having an ON DUTY ratio set according to the dimming rate of the dimming member 2A in the second cycle T2 over the next 1 / 4 of the first cycle T1 (for example, the period from time t3 to time t4 when the period from time t1 to time t5 in FIG. 3 is defined as the first cycle T1), and drives the first switching element Q3 and the second switching element Q2 with a PWM control signal having an ON DUTY ratio set according to the dimming rate of the dimming member 2B in the last 1 / 4 of the first cycle T1 (for example, the period from time t4 to time t5 when the period from time t1 to time t5 in FIG. 3 is defined as the first cycle T1).

[0031] The filter 30 is provided across a first node n1 (hereinafter referred to as “node n1”) at which a first switching element Q1 and a second switching element Q2 in one arm A1 of two arm sections A are connected, and a second node n2 (hereinafter referred to as “node n2”) at which a first switching element Q3 and a second switching element Q4 in the other arm A2 of the two arm sections A are connected. The node n1 at which the first switching element Q1 and the second switching element Q2 in the arm section A1 are connected is a portion at which the source terminal of the first switching element Q1 and the drain terminal of the second switching element Q2 constituting the arm section A1 are connected. The node n2 at which the first switching element Q3 and the second switching element Q4 in the arm section A2 are connected is a portion at which the source terminal of the first switching element Q3 and the drain terminal of the second switching element Q4 constituting the arm section A2 are connected. In this embodiment, the filter 30 is configured using an inductor FL1, an inductor FL2, and a capacitor FC1. In the filter 30, one of a pair of terminals of the inductor FL1 is connected to a node n1 in the arm A1, and one of a pair of terminals of the inductor FL2 is connected to a node n2 in the arm A2. Furthermore, a capacitor FC1 is provided between the other of the pair of terminals of the inductor FL1 and the other of the pair of terminals of the inductor FL2. The filter 30 smoothes the outputs from the two arms A into voltages corresponding to the dimming rates of the multiple dimming components 2. That is, the filter 30 smoothes the voltages output from the nodes n1 and n2 into voltages having a value corresponding to the dimming rate of the dimming component 2A over the first ¼ of the first period T1, and smoothes the voltages output from the nodes n1 and n2 into voltages having a value corresponding to the dimming rate of the dimming component 2B over the next ¼ of the first period T1.Next, the filter 30 smoothes the voltages output from the nodes n1 and n2 to voltages having a voltage value corresponding to the dimming rate of the dimming member 2A over the next 1 / 4 of the first period T1, and smoothes the voltages output from the nodes n1 and n2 to voltages having a voltage value corresponding to the dimming rate of the dimming member 2B over the final 1 / 4 of the first period T1.

[0032] The circuit breaker 40 includes a first circuit breaker 40H and a second circuit breaker 40L. The first circuit breaker 40H is provided at the first terminal 2C of each of the multiple light control components 2, and the second circuit breaker 40L is provided at the second terminal 2D of each of the multiple light control components 2. In this embodiment, the multiple light control components 2 are the light control component 2A and the light control component 2B. The first terminal 2C of each of the multiple light control components 2 is one of a pair of terminals that the light control component 2 has, to which an AC voltage for changing the dimming rate of the light control component 2 is applied. This corresponds to terminal 4A in the light control component 2A and terminal 4C in the light control component 2B. The second terminal 2D of each of the multiple light control components 2 is the other of the pair of terminals that the light control component 2 has, to which an AC voltage for changing the dimming rate of the light control component 2 is applied. This corresponds to terminal 4B in the light control component 2A and terminal 4D in the light control component 2B. In the following, the first circuit breaker 40H connected to terminal 4A of the light adjusting member 2A will be described as the first circuit breaker 40A, and the second circuit breaker 40L connected to terminal 4B of the light adjusting member 2A will be described as the second circuit breaker 40B. Also, the first circuit breaker 40H connected to terminal 4C of the light adjusting member 2B will be described as the first circuit breaker 40C, and the second circuit breaker 40L connected to terminal 4D of the light adjusting member 2B will be described as the second circuit breaker 40D. Also, when it is not necessary to distinguish between the first circuit breaker 40A and the first circuit breaker 40C, they will be described simply as the first circuit breaker 40H, and when it is not necessary to distinguish between the second circuit breaker 40B and the second circuit breaker 40D, they will be described simply as the second circuit breaker 40L.

[0033] The first cutoff unit 40H is configured to be able to cut off the electrical connection between the first terminal 2C and the node n1, and the second cutoff unit 40L is configured to be able to cut off the electrical connection between the second terminal 2D and the node n2. In this embodiment, as described above, one terminal of the inductor FL1 is connected to the node n1, and one terminal of the inductor FL2 is connected to the node n2. In this embodiment, the first cutoff unit 40A is provided between the terminal 4A of the light-adjusting member 2A and the node n3 to which the other terminal of the inductor FL1 is connected, and the second cutoff unit 40B is provided between the terminal 4B of the light-adjusting member 2A and the node n4 to which the other terminal of the inductor FL2 is connected. Furthermore, the first cutoff unit 40C is provided between the terminal 4C of the light-adjusting member 2B and the node n3 to which the other terminal of the inductor FL1 is connected, and the second cutoff unit 40D is provided between the terminal 4D of the light-adjusting member 2B and the node n4 to which the other terminal of the inductor FL2 is connected. Therefore, in this embodiment, the first terminal 2C of the dimming member 2 is connected to node n1 via the first interrupter 40H and the filter 30, and the second terminal 2D of the dimming member 2 is connected to node n2 via the second interrupter 40L and the filter 30.

[0034] In this embodiment, the first cutoff unit 40A is configured using an N-type MOS FET Q5 and an N-type MOS FET Q6. The drain terminal of the N-type MOS FET Q5 is connected to the node n3, and the source terminal of the N-type MOS FET Q5 is connected to the source terminal of the N-type MOS FET Q6. The drain terminal of the N-type MOS FET Q6 is connected to the terminal 4A of the light control member 2A. The gate terminals of the N-type MOS FET Q5 and the N-type MOS FET Q6 are connected to each other and to the second control unit 20. The anode terminal of a diode D5 parasitically provided between the drain and source terminals of the N-type MOS FET Q5 and the anode terminal of a diode D6 parasitically provided between the drain and source terminals of the N-type MOS FET Q6 are connected to each other, preventing current from flowing between the terminal 4A of the light control member 2A and the node n3 when both the N-type MOS FET Q5 and the N-type MOS FET Q6 are in the open state.

[0035] In this embodiment, the second cutoff unit 40B is configured using N-type MOS-FET Q7 and N-type MOS-FET Q8. The drain terminal of the N-type MOS-FET Q7 is connected to the terminal 4B of the light control member 2A. The source terminal of the N-type MOS-FET Q7 is connected to the source terminal of the N-type MOS-FET Q8. The drain terminal of the N-type MOS-FET Q8 is connected to the node n4. The gate terminals of the N-type MOS-FET Q7 and the N-type MOS-FET Q8 are connected to each other and to the second control unit 20. The anode terminal of a diode D7 parasitically provided between the drain and source terminals of the N-type MOS-FET Q7 and the anode terminal of a diode D8 parasitically provided between the drain and source terminals of the N-type MOS-FET Q8 are connected to each other, preventing current from flowing between the terminal 4B of the light control member 2A and the node n4 when both the N-type MOS-FET Q7 and the N-type MOS-FET Q8 are in the open state.

[0036] Furthermore, in this embodiment, the first cutoff unit 40C is configured using N-type MOS-FETs Q9 and Q10. The drain terminal of N-type MOS-FET Q9 is connected to node n3, and the source terminal of N-type MOS-FET Q9 is connected to the source terminal of N-type MOS-FET Q10. The drain terminal of N-type MOS-FET Q10 is connected to terminal 4C of the light control member 2B. The gate terminals of N-type MOS-FET Q9 and N-type MOS-FET Q10 are connected to each other and to the second control unit 20. The anode terminal of diode D9, which is parasitically provided between the drain and source terminals of N-type MOS-FET Q9, and the anode terminal of diode D10, which is parasitically provided between the drain and source terminals of N-type MOS-FET Q10, are connected to each other, preventing current from flowing between terminal 4C of the light control member 2B and node n3 when both N-type MOS-FET Q9 and N-type MOS-FET Q10 are in the open state.

[0037] In this embodiment, the second cutoff unit 40D is configured using an N-type MOS-FET Q11 and an N-type MOS-FET Q12. The drain terminal of the N-type MOS-FET Q11 is connected to the terminal 4D of the light control member 2B. The source terminal of the N-type MOS-FET Q11 is connected to the source terminal of the N-type MOS-FET Q12. The drain terminal of the N-type MOS-FET Q12 is connected to a node n4. The gate terminals of the N-type MOS-FET Q11 and the N-type MOS-FET Q12 are connected to each other and to the second control unit 20. The anode terminal of a diode D11 that is parasitically provided between the drain terminal and source terminal of the N-type MOS-FET Q11 and the anode terminal of a diode D12 that is parasitically provided between the drain terminal and source terminal of the N-type MOS-FET Q12 are connected to each other, and when both the N-type MOS-FET Q11 and the N-type MOS-FET Q12 are in the open state, a current is prevented from flowing between the terminal 4D of the light-adjusting member 2B and the node n4.

[0038] The second control unit 20 changes the cutoff state of the cutoff unit 40 based on a second period. The second period is a period in which the second control unit 20 outputs a PWM control signal to control the DC / AC inverter 10. In this embodiment, the second control unit 20 closes the cutoff unit 40 so that only a voltage corresponding to the dimming rate is applied to each of the multiple dimming components 2. That is, the second control unit 20 applies the AC voltage output from the DC / AC inverter 10 by closing the first cutoff unit 40H provided at the first terminal 2C of the dimming component 2 to be applied and the second cutoff unit 40L provided at the second terminal 2D of the dimming component 2 to be applied, and leaves the other first cutoff units 40H and second cutoff units 40L open.

[0039] Specifically, when applying the AC voltage generated by the DC / AC inverter 10 to the dimming member 2A, the second control unit 20 closes the N-type MOS-FET Q5 and N-type MOS-FET Q6 of the first cutoff unit 40A connected to the terminal 4A of the dimming member 2A and the N-type MOS-FET Q7 and N-type MOS-FET Q8 of the second cutoff unit 40B connected to the terminal 4B of the dimming member 2A, and opens the N-type MOS-FET Q9 and N-type MOS-FET Q10 of the first cutoff unit 40C connected to the terminal 4C of the dimming member 2B and the N-type MOS-FET Q11 and N-type MOS-FET Q12 of the second cutoff unit 40D connected to the terminal 4D of the dimming member 2B. Furthermore, when applying the AC voltage generated by the DC / AC inverter 10 to the light control member 2B, the second control unit 20 closes the N-type MOS-FET Q9 and N-type MOS-FET Q10 of the first cutoff unit 40C connected to the terminal 4C of the light control member 2B and the N-type MOS-FET Q11 and N-type MOS-FET Q12 of the second cutoff unit 40D connected to the terminal 4D of the light control member 2B, and opens the N-type MOS-FET Q5 and N-type MOS-FET Q6 of the first cutoff unit 40A connected to the terminal 4A of the light control member 2A and the N-type MOS-FET Q7 and N-type MOS-FET Q8 of the second cutoff unit 40B connected to the terminal 4B of the light control member 2A. This makes it possible to maintain the dimming ratio of each of the multiple light control members 2 constant.

[0040] In this embodiment, capacitors 50 are provided that are connected in parallel to each of the multiple light adjusting members 2. In this example, capacitor 50A is provided in parallel with light adjusting member 2A, and capacitor 50B is provided in parallel with light adjusting member 2B. One terminal of capacitor 50A is connected to terminal 4A of light adjusting member 2A, and the other terminal of capacitor 50A is connected to terminal 4B of light adjusting member 2A. Furthermore, one terminal of capacitor 50B is connected to terminal 4C of light adjusting member 2B, and the other terminal of capacitor 50B is connected to terminal 4D of light adjusting member 2B. As a result, when the N-type MOS-FET Q5 and N-type MOS-FET Q6 of the first cutoff unit 40A connected to the terminal 4A of the light control member 2A and the N-type MOS-FET Q7 and N-type MOS-FET Q8 of the second cutoff unit 40B connected to the terminal 4B are in a closed state, and the N-type MOS-FET Q9 and N-type MOS-FET Q10 of the first cutoff unit 40C connected to the terminal 4C of the light control member 2B and the N-type MOS-FET Q11 and N-type MOS-FET Q12 of the second cutoff unit 40D connected to the terminal 4D are in an open state, the capacitor 50B suppresses a decrease in the potential difference between the terminals 4C and 4D of the light control member 2B, and the light control When the N-type MOS-FET Q9 and N-type MOS-FET Q10 of the first cutoff unit 40C connected to the terminal 4C of the light control member 2B and the N-type MOS-FET Q11 and N-type MOS-FET Q12 of the second cutoff unit 40D connected to the terminal 4D are in a closed state, and the N-type MOS-FET Q5 and N-type MOS-FET Q6 of the first cutoff unit 40A connected to the terminal 4A of the light control member 2A and the N-type MOS-FET Q7 and N-type MOS-FET Q8 of the second cutoff unit 40B connected to the terminal 4B are in an open state, the capacitor 50A can suppress a decrease in the potential difference between the terminals 4A and 4B of the light control member 2A. Details will be described later.

[0041] Next, the operation of the dimming device 1 will be described using waveforms of each part of the dimming device 1 shown in Fig. 3. (a) of Fig. 3 shows the output voltage of battery B. Battery B outputs a DC voltage of a predetermined voltage value (V1 [V] in the example of Fig. 3). The DC voltage of battery B is applied to DC / DC converter 60 and first control unit 70. When voltage is applied from battery B, first control unit 70 drives DC / DC converter 60. As a result, DC / DC converter 60 outputs a DC voltage of a predetermined voltage value (V2 [V] in the example of Fig. 3) as shown in (b) of Fig. 3.

[0042] The output voltage of the DC / DC converter 60 is applied to the DC / AC inverter 10 and the power supply unit 80. The power supply unit 80 converts the output voltage of the DC / DC converter 60 into a voltage (allowable voltage) that can be applied to the second control unit 20 and applies the converted voltage to the second control unit 20. When the power supply unit 80 applies a voltage to the second control unit 20, the second control unit 20 drives the DC / AC inverter 10.

[0043] From time t1 to time t2, the second control unit 20 drives the DC / AC inverter 10 with a PWM control signal having an on-time Ta for the second cycle T2. The on-time Ta is set by an on-duty ratio corresponding to the dimming rate of the dimming component 2A. (c) of FIG. 3 shows the waveform of the voltage generated between nodes n1 and n2 at this time. This voltage is smoothed by the filter 30. The smoothed voltage (referred to as V4) is given by the following equation (1). (d) of FIG. 3 shows the waveform of the voltage (V4) generated between nodes n3 and n4 at this time.

number

[0044] The second control unit 20 also applies a signal higher than the potential of the source terminal to the gate terminals of N-type MOS FETs Q5 and Q6 of the first shutoff unit 40A connected to terminal 4A of the light control member 2A to which this voltage is applied, and to the gate terminals of N-type MOS FETs Q7 and Q8 of the second shutoff unit 40B connected to terminal 4B, in order to close these two gates. The second control unit 20 also applies a signal higher than the potential of the source terminal to the gate terminals of N-type MOS FETs Q7 and Q8 of the second shutoff unit 40B. The voltage waveforms applied to these gate terminals are shown in FIG. 3(e). As a result, as shown in FIG. 3(f), a voltage V4 is applied between terminals 4A and 4B of the light control member 2A between time t1 and time t2. At time t2, the second control unit 20 opens the N-type MOS-FET Q5 and N-type MOS-FET Q6 of the first cutoff unit 40A connected to the terminal 4A of the dimming member 2A and the N-type MOS-FET Q7 and N-type MOS-FET Q8 of the second cutoff unit 40B provided at the terminal 4B (see (e) of Figure 3).

[0045] Subsequently, from time t2 to time t3, the second control unit 20 drives the DC / AC inverter 10 with a PWM control signal having an on-time Tb of the second cycle T2. The on-time Tb is set by an on-duty ratio corresponding to the dimming rate of the dimming component 2B. (c) of FIG. 3 shows the waveform of the voltage generated between nodes n1 and n2 at this time. This voltage is smoothed by the filter 30. The smoothed voltage (denoted as V5) is given by the following equation (2). (d) of FIG. 3 shows the waveform of the voltage (V5) generated between nodes n3 and n4 at this time.

[0046]

number

[0047] The second control unit 20 also applies a signal higher than the potential of the source terminal to the gate terminals of N-type MOS-FET Q9 and N-type MOS-FET Q10 of the first cutoff unit 40C connected to terminal 4C of the light control member 2B to which this voltage is applied, and to the gate terminals of N-type MOS-FET Q11 and N-type MOS-FET Q12 of the second cutoff unit 40D connected to terminal 4D, in order to close these two gates. The second control unit 20 also applies a signal higher than the potential of the source terminal to the gate terminals of N-type MOS-FET Q11 and N-type MOS-FET Q12 of the second cutoff unit 40D. The voltage waveforms applied to these gate terminals are shown in FIG. 3(g). As a result, as shown in FIG. 3(h), a voltage V5 is applied between terminals 4C and 4D of the light control member 2B between time t2 and time t3. At time t3, the second control unit 20 opens the N-type MOS-FET Q9 and N-type MOS-FET Q10 of the first cutoff unit 40C connected to the terminal 4C of the dimming member 2B and the N-type MOS-FET Q11 and N-type MOS-FET Q12 of the second cutoff unit 40D connected to the terminal 4D (see (g) of Figure 3).

[0048] As described above, at time t2, the N-type MOS-FET Q5 and N-type MOS-FET Q6 of the first cutoff unit 40A connected to the terminal 4A of the light-adjusting member 2A and the N-type MOS-FET Q7 and N-type MOS-FET Q8 of the second cutoff unit 40B connected to the terminal 4B are set to the open state (see FIG. 3(e)), so that the output voltage of the DC / AC inverter 10 is not directly applied to the light-adjusting member 2A between time t2 and time t3. However, because the capacitor 50A is provided in parallel with the light-adjusting member 2A, the potential difference between the terminal 4A and the terminal 4B of the light-adjusting member 2A that occurred between time t1 and time t2 is maintained between time t2 and time t3 as shown in FIG. 3(f).

[0049] Between time t3 and time t4, the second control unit 20 drives the DC / AC inverter 10 with a PWM control signal having an on-time of Ta during the second period T2. At this time, the second control unit 20 drives the DC / AC inverter 10 to output an output voltage whose sign is opposite (inverted) from the output voltage of the DC / AC inverter 10 between time t1 and time t2. The waveform of the voltage generated between the nodes n1 and n2 at this time is shown in FIG. 3(c). This voltage is smoothed by the filter 30, and the waveform of the voltage (-V4) generated between the nodes n3 and n4 at this time is shown in FIG. 3(d).

[0050] As described above, at time t3, the N-type MOS-FET Q9 and N-type MOS-FET Q10 of the first cutoff unit 40C connected to the terminal 4C of the light-adjusting member 2B and the N-type MOS-FET Q11 and N-type MOS-FET Q12 of the second cutoff unit 40D connected to the terminal 4D are set to the open state (see FIG. 3(g)), so that the output voltage of the DC / AC inverter 10 is not directly applied to the light-adjusting member 2B between time t3 and time t4. However, because the capacitor 50B is provided in parallel with the light-adjusting member 2B, the potential difference between the terminal 4C and the terminal 4D of the light-adjusting member 2B that occurred between time t2 and time t3 is maintained between time t3 and time t4 as shown in FIG. 3(h).

[0051] Between time t4 and time t5, the second control unit 20 drives the DC / AC inverter 10 with a PWM control signal having an on-time of Tb in the second cycle T2. At this time, the second control unit 20 drives the DC / AC inverter 10 to output an output voltage whose sign is opposite (inverted) from the output voltage of the DC / AC inverter 10 between time t2 and time t3. The waveform of the voltage generated between the nodes n1 and n2 at this time is shown in FIG. 3(c). This voltage is smoothed by the filter 30, and the waveform of the voltage (-V5) generated between the nodes n3 and n4 at this time is shown in FIG. 3(d).

[0052] As described above, at time t4, the N-type MOS-FET Q5 and N-type MOS-FET Q6 of the first cutoff unit 40A connected to the terminal 4A of the light-adjusting member 2A and the N-type MOS-FET Q7 and N-type MOS-FET Q8 of the second cutoff unit 40B connected to the terminal 4B are opened (see FIG. 3(e)), so that the output voltage of the DC / AC inverter 10 is not directly applied to the light-adjusting member 2A between time t4 and time t5. However, because the capacitor 50A is provided in parallel with the light-adjusting member 2A, the potential difference between the terminal 4A and the terminal 4B of the light-adjusting member 2A that occurred between time t3 and time t4 is maintained between time t4 and time t5, as shown in FIG. 3(f).

[0053] The second control unit 20 controls the DC / AC inverter 10 and the circuit breaker 40 in the same manner as in the period from time t1 to time t5. This makes it possible to change the voltage value of the output voltage of the DC / AC inverter 10 in a period (T3) shorter than the first period T1 while switching the positive and negative polarities of the output voltage of the DC / AC inverter 10 in a first period T1 (for example, a period corresponding to the time from time t1 to time t5) (in this example, the voltage is changed in a period corresponding to the time from time t1 to time t2). By setting such a voltage in accordance with the dimming rate of each of the dimming components 2, the dimming device 1 can change the dimming rates of multiple dimming components 2 with a single DC / AC inverter 10.

[0054] Figure 4 shows the voltage waveform between the first terminal 2C and the second terminal 2D of the dimming member 2 when a capacitor 50 is provided in parallel with the dimming member 2, and the voltage waveform between the first terminal 2C and the second terminal 2D of the dimming member 2 when a capacitor 50 is not provided in parallel with the dimming member 2.

[0055] 4A corresponds to FIG. 3E and shows the waveform of the voltage applied to the gate terminals of N-type MOS-FETs Q5 and Q6 of the first cutoff unit 40A connected to terminal 4A of the light-adjusting member 2A and the gate terminals of N-type MOS-FETs Q7 and Q8 of the second cutoff unit 40B connected to terminal 4B. FIG. 4B corresponds to FIG. 3F and shows the waveform of the voltage generated between terminals 4A and 4B of the light-adjusting member 2A. The solid line shows the waveform of the voltage generated between terminals 4A and 4B of the light-adjusting member 2A when a capacitor 50A is provided in parallel with the light-adjusting member 2A, and the dashed line shows the waveform of the voltage generated between terminals 4A and 4B of the light-adjusting member 2A when a capacitor 50A is not provided in parallel with the light-adjusting member 2A.

[0056] As shown in FIG. 4, when the capacitor 50A is not provided in parallel with the light adjusting member 2A, if a voltage is not applied to the gate terminals of the N-type MOS-FETs Q5 and Q6 of the first cutoff unit 40A connected to the terminal 4A of the light adjusting member 2A and the gate terminals of the N-type MOS-FETs Q7 and Q8 of the second cutoff unit 40B connected to the terminal 4B, that is, when the N-type MOS-FETs of the first cutoff unit 40A and the second cutoff unit 40B are in the open state, the potential difference between the terminals 4A and 4B of the light adjusting member 2A gradually decreases. However, when a capacitor 50A is provided in parallel with the dimming member 2A, even if no voltage is applied to the gate terminals of the N-type MOS-FETs Q5 and Q6 of the first cutoff unit 40A connected to terminal 4A of the dimming member 2A and the gate terminals of the N-type MOS-FETs Q7 and Q8 of the second cutoff unit 40B connected to terminal 4B of the dimming member 2A, that is, even if the N-type MOS-FETs of the first cutoff unit 40A and the second cutoff unit 40B are in the open state, the potential difference between terminals 4A and 4B of the previous dimming member 2 is maintained. In this way, by providing the capacitor 50, the potential difference between the first terminal 2C and the second terminal 2D of the dimming member 2 can be maintained at a potential difference corresponding to the desired dimming rate, and changes in the dimming rate of the dimming member 2 can be suppressed.

[0057] As described above, the light control device 1 can individually change the dimming rate of each of the plurality of light control members 2. The control of the light control device 1 described above can also be defined as a light control method in which a computer individually changes the dimming rate of each of the plurality of light control members 2.

[0058] First, the second control unit 20 (an example of a computer) of the light control device 1 sets an on-duty ratio according to the desired dimming rate for each of the plurality of light control members 2. That is, the second control unit 20 sets an on-duty ratio according to the dimming rate for the light control member 2A and an on-duty ratio according to the dimming rate for the light control member 2B. The step of setting the dimming rate for each of the plurality of light control members 2 corresponds to the setting step in the above-mentioned light control method.

[0059] Next, the second control unit 20 of the dimming device 1 controls the DC / AC inverter 10, which can convert a DC voltage into an AC voltage having a predetermined first period T1, based on a PWM control signal with an on-duty ratio set in the setting step, so that the period of the AC voltage includes an output voltage with a second period T2 shorter than the first period T1. That is, the second control unit 20 sets an on-time (e.g., Ta) of the second period T2 from the on-duty ratio corresponding to the dimming rate of the dimming member 2A set in the setting step, and sets an on-time (e.g., Tb) of the second period T2 from the on-duty ratio corresponding to the dimming rate of the dimming member 2B. The second control unit 20 drives the DC / AC inverter 10 with the PWM control signals with the on-times Ta and Tb set for the dimming members 2A and 2B sequentially every ¼ of the first period T1. In this case, if the first period T1 is divided into four periods, with the first period being the first period, the second period being the second period, the third period being the third period, and the fourth period being the fourth period, the second control unit 20 controls the DC / AC inverter 10 so that the positive and negative voltage values ​​of the voltage output from the DC / AC inverter 10 are reversed in the first and third periods, and controls the DC / AC inverter 10 so that the positive and negative voltage values ​​of the voltage output from the DC / AC inverter 10 are reversed in the second and fourth periods. The step of controlling the DC / AC inverter 10 in this way corresponds to the control step in the above-mentioned dimming method.

[0060] At this time, during the first period and the third period, the second control unit 20 closes the MOS-FET of the first cut-off unit 40A connected to the terminal 4A of the dimming member 2A, closes the MOS-FET of the second cut-off unit 40B connected to the terminal 4B of the dimming member 2A, opens the MOS-FET of the first cut-off unit 40C connected to the terminal 4C of the dimming member 2B, and opens the MOS-FET of the second cut-off unit 40D connected to the terminal 4D of the dimming member 2B. Moreover, during the second and fourth periods, the second control unit 20 closes the MOS-FET included in the first cutoff unit 40C connected to the terminal 4C of the light adjusting member 2B, closes the MOS-FET included in the second cutoff unit 40D connected to the terminal 4D of the light adjusting member 2B, opens the MOS-FET included in the first cutoff unit 40A connected to the terminal 4A of the light adjusting member 2A, and opens the MOS-FET included in the second cutoff unit 40B connected to the terminal 4B of the light adjusting member 2A. Such control to change the state (open / closed state) of the MOS-FET included in the cutoff unit 40 is also performed in the control step.

[0061] The light control device 1 (the second control unit 20 of the light control device 1) can change the dimming rate of each of the plurality of light control members 2 by using the light control method in this way.

[0062] Other Embodiments In the above embodiment, an example was given in which the dimming member 2 is provided on the roof panel of the vehicle 3, but the dimming member 2 may also be provided on a side window, rear window, front window, etc. of the vehicle 3.

[0063] In the above embodiment, an example has been described in which a plurality of light control members 2 are provided on the vehicle 3. However, the light control member 2 may be provided on something other than the vehicle 3 (for example, a building), and the light control device 1 may be configured to change the dimming rate of the light control member 2 provided on something other than the vehicle 3.

[0064] In the above embodiment, an example has been described in which there are two dimming components 2. The number of dimming components 2 may be three or more. In this case, by dividing a half cycle of the AC voltage having the first period T1 into periods according to the number of dimming components 2 and controlling the generation of voltages with on-duty ratios according to the dimming rates of the respective dimming components 2 during those periods, it becomes possible to change the dimming rates of the multiple dimming components 2 with one DC / AC inverter 10.

[0065] In the above embodiment, it has been described that the filter 30 is provided between the node n1 and the node n2, and that the filter 30 includes the inductor FL1, the inductor FL2, and the capacitor FC1. The filter 30 may be composed of components other than the inductor FL1, the inductor FL2, and the capacitor FC1 as long as the components are capable of smoothing the output voltage of the DC / AC inverter 10, or may be composed of at least one of the inductor FL1, the inductor FL2, and the capacitor FC1 in combination with other components.

[0066] In the above embodiment, the dimming device 1 is described as being provided with a cutoff unit 40 having a first cutoff unit 40H that can cut off the electrical connection between the first terminal 2C of each of the multiple dimming components 2 and node n1, and a second cutoff unit 40L that can cut off the electrical connection between the second terminal 2D of each of the multiple dimming components 2 and node n2. However, the dimming device 1 can be configured with a cutoff unit 40 that has either the first cutoff unit 40H or the second cutoff unit 40L, or can be configured without a cutoff unit 40.

[0067] In the above embodiment, the second control unit 20 has been described as closing the cutoff unit 40 so as to apply only a voltage corresponding to the dimming rate to each of the plurality of dimming components 2, but the second control unit 20 may also control the cutoff unit 40 so as to apply a voltage corresponding to the dimming rate of each of the plurality of dimming components 2 to each of the plurality of dimming components 2.

[0068] In the above embodiment, the capacitor 50 is connected in parallel to each of the plurality of dimming members 2, but it is also possible to configure the light control device without the capacitor 50. In this case, it is preferable to increase the second frequency so that the potential difference between the first terminal 2C and the second terminal 2D of the light control member 2 can be maintained at a potential difference according to the desired dimming rate.

[0069] The present invention can be used in a light control device that individually changes the dimming rate of each of a plurality of light control members, and in such a light control method. [Explanation of symbols]

[0070] 1: Dimmer 2: Dimming material 2C: 1st terminal 2D: 2nd terminal 10: DC / AC inverter 20: Second control unit (control unit) 30: Filter 40: Cut-off section 40H: First interrupter 40L: Second cutoff section 50: Capacitor A: Arm A1: Arm part (one arm part) A2: Arm part (other arm part) L1: First power line L2: Second power line n1: Node (first node) n2: Node (second node) Q1: First switching element Q2: Second switching element Q3: First switching element Q4: Second switching element QH: First switching element QL: Second switching element T1: 1st period T2: 2nd period

Claims

1. A light control device that individually changes the dimming rate of each of a plurality of light control members, a DC / AC inverter capable of converting a DC voltage into an AC voltage having a predetermined first period; a control unit that controls the DC / AC inverter based on a PWM control signal having an on-duty ratio corresponding to a desired dimming rate for each of the plurality of dimming members so that an output voltage having a second period shorter than the first period is included within a period of the AC voltage; A dimmer comprising:

2. the DC / AC inverter has two arms, each having a first switching element and a second switching element connected in series, that are provided between a first power supply line and a second power supply line, and a filter provided across a first node, at which the first switching element and the second switching element in one of the two arms are connected, and a second node, at which the first switching element and the second switching element in the other of the two arms are connected; The light control device according to claim 1 , wherein the filter smoothes the outputs from the two arms into voltages according to the dimming rates of the plurality of dimming members.

3. The light control device further includes a blocking unit including: a first blocking unit provided on a first terminal of each of the plurality of light control members and capable of blocking an electrical connection between the first terminal and the first node; and a second blocking unit provided on a second terminal of each of the plurality of light control members and capable of blocking an electrical connection between the second terminal and the second node; The light control device according to claim 2 , wherein the control unit outputs the PWM control signal in the second cycle and changes the cut-off state of the cut-off unit based on the second cycle.

4. The light control device according to claim 3 , wherein the control unit closes the cutoff unit so that only a voltage according to the dimming rate is applied to each of the plurality of dimming members.

5. The light control device according to claim 1 , further comprising a capacitor connected in parallel with each of the plurality of light control members.

6. A dimming method in which a computer individually changes the dimming rate of each of a plurality of dimming members, a setting step of setting an on-duty ratio according to a desired dimming rate for each of the plurality of dimming members; a control step of controlling a DC / AC inverter capable of converting a DC voltage into an AC voltage having a predetermined first period based on a PWM control signal of the on-duty ratio so that an output voltage having a second period shorter than the first period is included in the period of the AC voltage; A dimming method comprising: